Behavioural response of the greater horseshoe bat to geographical variation in echolocation calls

The geographical variation in animals' social acoustical signals can reduce recognition across populations and may thus promote assortative mating, reproductive isolation and speciation. However, the social consequences of geographical variation in acoustical signals serving an ecological function are poorly known. Bat echolocation calls are considered to have a dual function; they are used not only for orientation and foraging but also for communication. In this study, we studied the behavioural response of Rhinolophus ferrumequinum to geographical variation in echolocation calls. Using habituation-dishabituation playback experiments, we found that all tested bats from northeast China exhibited obvious responses after switching playback from their own population to those from central east China and southwest China. Using two-choice playback experiments, we showed that the bats from northeast China responded more strongly to echolocation calls from their own population than to those from central east China. Our results demonstrate that Rhinolophus ferrumequinum is able to discriminate between echolocation calls of its local population and a foreign one and that local echolocation calls are preferred over foreign ones in a two-choice context. This study supports the communicative potential of bat echolocation calls and provides insight into the discrimination ability and behavioural preference of bats with respect to geographical variation in echolocation calls. This study provides behavioural evidence for the communicative role in echolocation calls and indicates that a dual function of echolocation calls exists more commonly in bats. Moreover, this study provides insight into the discrimination ability and preference of bats with respect to frequency variation in echolocation calls and contributes to a better understanding of how geographical evolution in ecological acoustical signals may affect the ability of recognition between populations.